Hi! I am new here. I am a fluent speaker of Esperanto despite the fact that I have two mother languages (first languages) that are rather widely spoken around the world: American English and German.
At this point in time, Esperanto is no more artificial than Hochdeutsch or Cambridge English, both of which have been purposefully and consciously shaped by a group of people. Esperanto has slang (lots of it), dialects, and is used in daily life (e.g. in my house). My partner is Brazilian and so we both have acquied the other guy's language (well, his German is still a work in progress).
I have made love in Esperanto, sworn in Esperanto and used Esperanto to talk about grocery shopping and who should wash the dishes. I have also dreamed (or dreamt) in Esperanto.
There are native speakers of Esperanto (George Sorros is one of them). New words come into the language (e.g. "mojosa" - means something like "cool" in English. Noone knows how that word came about, it just did.)
Esperanto is not, as someone here wrote, a bouquet of plastic flowers. It is a living language. In fact, there are no non-artificial languages. All languages were created by humankind. Unless you are an evangelical protestant and believe that God created language and passed it down to us, then you must believe that humans created language.
I don't mean to contradict anyone here but I feel as hurt by some of the things people say about "my" language as they would if I were to make fun of their language. Furthermore, I have the impression that some of those who criticize Esperanto don't speak it or have ever studied it.
jI recently delivered a paper at a conference on the use of morphology in teaching Chinese vocabulary and was surprised when I was writing the paper that Chinese "creates" words in the same way that Esperanto does and that both languages have a large body of unbound morphemes which can be used as heads or codas for new words, which is not true of most European languages.